Hugelkultur: Composting Whole Trees For The Ultimate Raised Garden Bed

Hugelkultur (HOO-gul-culture) is a German word meaning mound culture or hill culture.

Hugelkultur is simply old logs and debris buried under top soil. Over time, the decomposing logs retain moisture and release a sustained stream of nutrients into the soil. This type of raised bed needs very little care or irrigation.

The decaying wood at the bottom of the mound is the ultimate long-term source of nutrients for plants and trees. Depending on the size of the mound and the amount of logs used a mound may produce nutrients in excess of 20 years. The logs and branches also become a kind of reservoir. Water is stored within the decaying timbers and is essentially released during dry spells. Which means you may never have to water the garden. The composting wood also generates heat which can extend the growing season of some plants and vegetables.

Creating your own Hugelkultur mound takes a little time and energy. You can make your mound as long as you like but it's best practice to make it only 5 or 6 feet wide. Mounds can be made on top of the ground or a trench can be dug to a depth of two feet. For best results mounds should be at least 3 feet high.

I prefer digging a trench about 2 feet deep and lining the bottom of the trench with softball sized rock to allow for proper drainage.

Once the bed is properly lined with a layer of stone or rock you can begin adding your logs, branches, and leaves. Hardwood is best as it will take longer to decay. Avoid using trees like cedar, black walnut, pine, and maple. These trees will actually inhibit the growth of many plants and vegetables.

Add a layer of manure approximately 2” thick on top of the logs, branches and debris. Fill all voids between logs with manure. Then add 3” inches of top soil. Spray everything down with a water hose until everything is well soaked.

Add additional layers of leaves, manure, and top soil until you reach a height of at least 3 feet.

Top everything off with a layer of straw to keep rain from washing away the soil.

The benefits of the Hugelkultur really begin to kick in after the first year as the logs begin to decompose. This style of raised garden bed produces some of the best annual vegetables. Perennial vegetables such as asparagus, rhubarb, and sun-chokes do amazingly well the first year and do even better the following years once their root structures are established.